Screen for bolting flour



{No Model.)

0. P. HURFORD.

SCREEN FOR BOLTING FLOUR. No. 399,616. Patent-ed Mar. 12, 1889.

HM 1 I B E 2 5 i X Fig.1

WITNESS-ES: v IIVVEIVIORI d; I QZgvcrl?Hmjoj-d ATTORNEY. I

Miran Starts Parasr Fries.

oLivER r. neurons, or our uico, 'rtrmors.

senses-i roe sorrme FLOUR.

SFECIFICATION forming part of Letters Patent No. 399,616, dated March12, 1889.

Application filed April 5,1888. Serial No. 269,700. (No as.)

T 0 all whom it may concern:

Be it known that I, OLIVER P. HURFORD, of Chicago, in the county of.Cook and State of Illinois, have invented a new and useful Improvementin Screens for Bolting Flour; and

I do hereby declare that the following is a full, clear, and exactdescription thereof, reference being had to the accompanying drawings,making part of this specification.

My invention relates to that class of screening-machines (either flat ortubular in form) in which the screening-surface is located in,

particles or grades of the flour boltin -surfaces composed of a wovensilk fabric. the use ef' such wire-Woven fabric (employed mostly in.those screens familiarly known as scalpers more or less difficultyarises from the fact that in 'practicaloperation this ordinarywoven-wire fabric is of such a struct ural character that not only arepocket-like recesses (of comparatively great capacity) afforded withinwhich numerous collections of the small particles of the material beingtreated accumulate and pack, thus more or less clogging up the meshes ofthe screen and impeding the flowing over its surface freely, and thepassage through its meshes easily of the particles of material whichshould readily pass through the screen, but, furthermore,

(the structural character of this ordinary wire screen) is such that itsinnumerable abrupt projections so forcibly oppose the action of thebrushing device (that must be employed in all such screeningcontrivances) as to very rapidly wear out the brush. Again, a thoroughcleaning off of (or cleaning out of the meshes of) the screenin-surface, or, in other words;a perfect clearance of the meshes of i thescreening-surface, is rendered difiicult, if

not impracticable, by reason o f the constant.

presence of the accumulated flour in the pocket-like recesses just abovereferred to,

which flour tends to pasteoier the meshes during the brushing operation,and to thus partially destroy the eificiency of the screen.

I propose by my improvement to provide for use a woven-wirescreening-surface which shall be comparatively free from the objectionsjust explained as being peculiar to such wire screens as have beenheretofore made and used; and to this main end and object my inventionmay be said to consist, essentially, in a wire-woven screening-surfacehaving all the projecting portions or points of the interlaced wiresflattened, (in any suitable manner, preferably by subjecting theordinary woven-wire fabric to a rolling or calendering opcration,-) soas to render the operative surface of the screen comparatively smooth,and so as to also very materially lesence to the accompanying drawings,which form a part of this specificatiomand in which I have shown myinvention carried into effect in two (of the various well known) formsof screening-machine to which it is applicable.

In the drawings, Figure 1 is a side view of an ordinary form ofcylindrical scalpel or screening -'machinc such as now commonly used inliouring-mills, but embodying my improvement.

ingmore particularly the relative arrangement with the cylinder of oneof the usual forms of brushing devices and illustrating the presence ofthe material that is fed into, re-

tained in, and passed through the screeningcylinder. Fig. 3 is alongitudinal perspectiy e of so much of a machine provided witlra iiatscreening-surface as it is necessary to show for the purpose ofexhibiting and explaining the application of my improvement to this 9Fig. 2 is a vertical cross-section of the cylinder at the line a: :1 ofFig. 1, showand 3, in which figures, however, the scale is too small topermit anyintelligible illustration of the precise structure of saidwoven fabric. Fig.6 is a skeleton. or sort of diagrammatical Viewshowing, on an exaggerated scale and in cross section, portion of ascreen made in 'the old-fashioned way and illustrating how the flour isapt to lodge within the small pocket-like recesses of the woven-wirefabric. Fig. 7 is a similar view of portion of a screen such'as seen atFigs. '1, 2, and 3, made according'to my invention and illustrating theaction of such improved screening device.

Each of the sectional views 6 and '7 .is drawn on a plane of sectionpassing adjacent to one of the, strands of the woven-wire fabric of Ywhich the screen is (in each case) supposed to .be-made, andlimall theviews in which arrows are seen they indicate the directions of vmovement of the screens,a nd also of the material being treated.

\Vherever the same part is shown in differentfigures it will be founddesignated by the same letter.

In the machine shown at'Figs l and 2, A is the screening-cylinder,constr'ucted,'mounted, and operating in the usual and well-known manner,except that its screening-surface is composed of a diiferent sort ofwoven-wire fabric, and Bis the brushing device, arranged and operatingin one of the well-known ways.

In Fig. 3'the flat screen 0 is constructed, mounted, and suitablyagitated with'a sort of reciprocatory motion, all in the usual wellknownmanner; except that the woven-wire fabric composing thescreening-surface is,

I like that of the cylindrical machine shown, of

a difierent structural character.

In both forms of machine shown as embodying my invention the screeningsurface (marked A in one case and G in the other) is made of a fabricthat is firstywoven of wire strands of equal size and exactly similar tothe fabric heretofore used, and that is subsequently subjected topressure superficially,

(preferably by passing the fabricated material betweencompressing-rollers,) so as to upset the stock of and flatten out (so tospeak) -all the abruptly-projecting portions or all the superficialprotuberances of the fabric at the localities where the interlacedmetallic strands overlie (or undei'lie) each other. In other words, themetallic woven fabric of which these screening-surfaces are composed isone which results from taking the fine woven-wire.

abric, heretofore usually employed in the construction of screens andsubjecting it to superficial pressure (preferably by passing it betweencompressing-rolls) in such manner and to such extent as to change itscondition from that shown at Figs. at and 6 (which show theold-fashioned fabric) to that seen at Figs. .5 and 7, which show thefabric used in my improved machine; and by a reference to and comparisonof what is'shown, respectively, in Figs. 4 and 6 and 5 and 7 it will bereadilyseen that while in the fabric heretofore employed in theconstruction of screening-machines the I multitudinous abruptprojections e (see Figs. land 6) present serious obstruction to a freetumbling and sliding movement over the screening-surface of theparticles designedto be passed through'the meshes of the screen, thissource of obstruction to a free movementof these particles over the saidscreening-surface has been in a great degree removed in the fabric usedin my improved machines,

since'by the flattening down of these pro jections, as seen at f, (seeFigs. 5 and 7,) the metallic superfices of the screen have been renderedsmoother. In other words, by thus flattening out (or mashing down) allthe abrupt projections, as shown at Figs. 5 and 7, the asperities of theold-fashioned screening surface have been materially softened orremoved, so that the light and fine particles of the mass of thematerial supported upon and agitated on the screening-surface of theimproved machine will move oversaid surface with more freedom, and hencebe afforded more opportunities topass through or greater in findingtheir way through the meshes of the screen; Furthermore, in a machineprovided with the kind of fabric shown at Figs. 5 and 7, as bothsurfaces of the fabric are thus smoothed, so to s'peak, the brushemployed to keep'the screen clear or clean (whether applied to one orthe other of the surfaces of the woven 'fabric) will not be abraded byfrictional contactwith the screen nearly as much, and consequently willnot be worn ,out (or have its eificiency impaired) nearly as soon as thebrushing devices used in machines provided with the old-fashioned kindof metallic screening device.

'The comparison of this new kind of flourscreening machine fabric withthe old-fashioned sort also shows that while in the kind seen at Figs. 4and 6 the interstices or receptacle-like recesses (seen at g) are ofsuflicient capacity to retain considerable quantities of the flour,these recesses in the kind of fabric shown at Figs. 5 and 7 are, asshown at also reduced in size and in their capacity to retain portionsof the fine particles of the material being treated as to practicallyovercome a heretofore serious difficultyviz., the

rapid accumulation in these interstices of sufficient quantities of theflour to not only partially clog the meshes, and thus impair theirfunction, but to also cause the pasting IIO over of thescreening-surface by the action of the brush on these accumulationsofflour.

stock in-roller milling the common wovenwire cloth rasps orgrates oif alarge portion of fiuif and fine middlings, which go into the flour todiscolorit and increase the proportion of the lower or less valuablegrades.

Then in grading the nliddlings, after having.

consequently thrown to the dust-room, at a been scalped off, thesmooth-surfaced .or flattened wire-cloth does not wear or flour themiddlings, in consequence of which a large portion of flour is sent tothe purifiers, and

' great loss to the miller, as does the old-fashioned rough-surfacedcloth. 7

By the use of the flattened or smoother snrfacedwoven-wirescreening-surface the machine is adapted to the grading oftheffinerqualities of middlings, which heretofore could he done only on a kind ofsilkcloth known as grits-gauze at a heavy expense,,asy-the sharpmiddlings cut out the grits-gauze very rapidly, rendering itnece'ssaryto frequently :replace it. The smooth-surfaced wire-cloth does the workequally as well-and will last a year.

'Among other and minorjadvantages to the screening-machine resultingfrom the-use therein of a bolting or screening wire fabric of thenovelcharacter herein shown and described may be mentioned -tl1 e;ironing out (so to'speak) of all the pnckers or'superficial wave-likeirregularities,-i which always exist in fine woven-wire fabrics as theycomefrom the weaving-machine, whereby. a' fabric for thescreening-surface (whether flat or curved) is provided for usethat maybeformed into I either aperfect plain or a perfect curve, so

' that the brushing device will properly sweep over every pointthroughont the whole surface designed to be acted uponby such brush.

Furthermorain the use of such a metallic fabric, for the screen themeshes may be made smaller and-hence ,ajfiner wire screen can beemployed (wherever this may be desirable) than could :possibly'be usedin the construe tion of a wire screen as heretofore made.

7 Having now so fully explained the construetion and operation .of my.improved flourscreening machine that those skilled in the art canreadily understandand practice my invention, and wishing itito beunderstoodthat I do not claim, broadly, as anew manu facture, aflattened woven-wire fabric, such a fabric being old per 86', what 1110claim as new, and desire to secure by Letters Patent,

15 .A linachine for screening. .-or bolting'fiour 'h'aving"screening-surface composed of a flattened woven-wire fabric,substantially as and for the purposes set forth.

In witnesswhereof I have hereunto set my hand this 30th day of March,1888. 7

OLIVER -P., HURFORD.

In presence of E. A. T RNER,

W. P. SISSON.

